The syntax for using the nysqldump command to export a database is. This shows us the following:

Access to the username database;

Mysqldump may ask you for a password;

Following are the processes that will tell us about backing up databases to an SQL file named name.sq

Restore your database

Primarily! If something went wrong for you, you can easily restore your database. Log in to get started

mysql -u username -p

Then create a new database

CREATE DATABASE newdb;

Quit MySQL

exit

After that, you can import the SQL file into a new database

mysql -u username -p newdb < name.sql

This completes the process of importing your SQL file into a new database!

Backup process

We recommend a way to back up a MySQL or MariaDB database using the mysqldump dump command.

echo "SHOW DATABASES;" | sudo mysql

This command displays a list of your databases. Make sure you know which .sql file you need, and then simply run the following command to backup to the file.

sudo mysqldump example_database > $(date +"%F").sql

The command described above will back up the example_database to a file with a date ending in .sql. It is also possible to change the name of this file to any other, although saving the file name as a date will be useful if you accidentally delete an important row or column. Use date –help to learn about other ways to style your date.

Recovery

Here you need to find the .sql file that you created and run the following:

sudo mysql example_database < filename.sql

Migrating to MariaDB from MySQL

The first thing to do is back up each of your databases:

sudo mysqldump example_database > example_database.sql

After that, you will need to install MariaDB, which will replace MySQL, and restore your databases by following these steps for each database.

sudo mysql example_database < example_database.sql

Copying your data from the Ubuntu server

First, you need to be logged in as a user with root privileges. After successful login, you need to check the list of databases. This can be done by entering a simple command:

mysql -u USERNAME

Further, after a successful login, you need to enter a special command that will provide you with the entire list of databases. This command looks like this:

SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| test_data          |
| important_db       |
| information_schema |
| mysql              |
| performance_schema |
+--------------------+
5 rows in set (0.012 sec)

Then you can close the command line by typing exit;

Using Mysqldump

You may need to use a password for login. To do this, just add -p to the command below. If you need to keep all databases, you can use the shortcut –all-databases instead of –databases names

mysqldump -u USERNAME --databases test_data important_db > database_dump.sql

Then the file is automatically generated. It will be named “database_dump.sql”. Its content includes all data for restoring the databases that you specify.

Protecting Your Backup Process

An important recommendation: if the data in the database contains sensitive data, then you should definitely encrypt it before you save or start the process of moving between servers. Run the first command below and then enter your password; it will not appear on your screen.

openssl enc -aes-256-cbc -pbkdf2 -in database_dump.sql -out database_dump.sql.enc
  enter aes-256-cbc encryption password:
  Verifying - enter aes-256-cbc encryption password:


rm database_dump.sql

In order for you to be able to decrypt your backup, you can use a special command, which is indicated below:

openssl enc -d -aes-256-cbc -pbkdf2 -in database_dump.sql.enc -out database_dump.sql
  enter aes-256-cbc encryption password:

The process of moving a backup

During the backup process, the .sql size can be bulky in size. This will negatively affect the file and data transfer process. Instead, you can use tools such as rsync to exchange data directly between servers.

rsync -a ./database_dump.sql user@185.186.244.123:/tmp/

185.186.244.123 – should be changed to your server address
user is the username on the remote server
tmp/ – should be replaced with your remote server directory

To restore your database, you can use the special mysql utility, an example is shown below:

mysql -u USERNAME <database_dump.sql

The most important task of the administrator is regular backup, it is an integral part of working with databases. The first thing to start is updating all system packages

Updating System Packages

Before starting, update the packages on your server

sudo apt-get update -y
sudo apt-get upgrade -y

PostgreSQL installation

PostgreSQL is available in the Ubuntu 18.04 repository and can be installed very simply with the following command:

sudo apt-get install postgresql postgresql-contrib

Then you should start the postgresql service and enable it at boot time:

sudo systemctl start postgresql
sudo systemctl enable postgresql

Backup Instructions

PostgreSQL comes with the pg_dump utility for calling information from the database to a file. You can run this utility from the command line interface. For example, if you want to back up one database, run the following command:

sudo pg_dump -U user_name database_name > backup_file

IMPORTANT! The command must be run as root.

You can follow another way: backup the database by logging in as a postgres user:

sudo su - postgres
pg_dump postgres > postgres.bak

This command (which is indicated above, respectively) backs up the default database postgres.

Also, using the command below, it is possible to backup a remote database:

pg_dump -U user_name -h remote_ip_address -p remote_port database_name > backup_file

If you want to backup all the databases on your system, then pg_dumpall then you can use:

sudo pg_dumpall -U user_name > backup_file

Restore Instructions

Next, we will discuss how to restore the database created by the pg_dump command using the psql command, but first you need to create a empty base with name new_database

sudo -u postgres psql
createdb -T template0 new_database

Then you need to redirect the database dump caused by backup_files with the following command:

psql new_database < backup_file

It happens that errors are made during the backup process, and you urgently need to stop the recovery process when an error occurs, run the following command:

psql --set ON_ERROR_STOP=on new_database < backup_file

To restore the databases created by the pg_dumpall command, transfer the file to sql. You can use this command:

psql -U user_name -f backup_file   

We recommend that you regularly store and back up!